package com.javaxiaobear.base.common.filter;

import com.javaxiaobear.base.common.utils.StringUtils;
import com.javaxiaobear.base.common.utils.html.EscapeUtil;
import jakarta.servlet.ReadListener;
import jakarta.servlet.ServletInputStream;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletRequestWrapper;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import org.apache.commons.io.IOUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;

/**
 * XSS过滤处理
 *
 * @author javaxiaobear
 */
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {
  public XssHttpServletRequestWrapper(HttpServletRequest request) {
    super(request);
  }

  @Override
  public String[] getParameterValues(String name) {
    String[] values = super.getParameterValues(name);
    if (values != null) {
      int length = values.length;
      String[] escapesValues = new String[length];
      for (int i = 0; i < length; i++) {
        // 防xss攻击和过滤前后空格
        escapesValues[i] = EscapeUtil.clean(values[i]).trim();
      }
      return escapesValues;
    }
    return super.getParameterValues(name);
  }

  @Override
  public ServletInputStream getInputStream() throws IOException {
    // 非json类型，直接返回
    if (!isJsonRequest()) {
      return super.getInputStream();
    }

    // 为空，直接返回
    String json = IOUtils.toString(super.getInputStream(), StandardCharsets.UTF_8);
    if (StringUtils.isEmpty(json)) {
      return super.getInputStream();
    }

    // xss过滤
    json = EscapeUtil.clean(json).trim();
    byte[] jsonBytes = json.getBytes(StandardCharsets.UTF_8);
    final ByteArrayInputStream bis = new ByteArrayInputStream(jsonBytes);
    return new ServletInputStream() {
      @Override
      public boolean isFinished() {
        return true;
      }

      @Override
      public boolean isReady() {
        return true;
      }

      @Override
      public int available() throws IOException {
        return jsonBytes.length;
      }

      @Override
      public void setReadListener(ReadListener readListener) {}

      @Override
      public int read() throws IOException {
        return bis.read();
      }
    };
  }

  /** 是否是Json请求 */
  public boolean isJsonRequest() {
    String header = super.getHeader(HttpHeaders.CONTENT_TYPE);
    return StringUtils.startsWithIgnoreCase(header, MediaType.APPLICATION_JSON_VALUE);
  }
}
